Brake service signaling system

Abstract

A brake service signaling system for use on a vehicle responsive to the angular relationship between an actuator lever arm and an actuator rod having an attachment clevis where a switch electrically connected to a processing unit is mounted to the attachment clevis for contact and activation with the actuator lever when the brake requires service which is signaled to the operator by the processing unit.

We claim:  
     
       1. A combination brake lining wear indicator and braking system, said combination comprising: 
       opposed brake shoes pivotally moveable by means of an “S” cam carried for rotation on a cam shaft and activated by a radially extending actuator lever arm connected to an actuator rod by an attachment clevis; and  
       an electrical switch mounted on said attachment clevis disposed to contact said actuator lever arm and become activated when said actuator lever arm rotates to a predetermined point associated with excessive wear of said brake linings, wherein when said electrical switch is activated said electrical switch generates a signal indicative of excessive wear of said brake linings.  
     
     
       2. A brake wear indicator system in a braking system having opposed brake shoes each including a brake lining mounted thereon, said brake shoes being pivotally moveable and actuated by movement of a radially extending actuator lever arm connected to an actuator rod by an attachment clevis-, said brake wear indicating system comprising: 
       a switch having an actuation plunger mounted to a mounting boss extending from said attachment clevis, said attachment clevis disposed so that said actuation plunger directly contacts said actuator lever thereby activating said switch only when said actuator lever arm rotates to a predetermined position as a result of excessive wear of said brake linings; and  
       a processing unit electrically connected to said switch for processing a first signal generated by said switch and generating a second signal indicative of said excessive wear of said brake linings in response to said first signal.  
     
     
       3. A brake service indicating system comprising: 
       a brake spider; a pair of opposite brake shoes rotatably mounted to said brake spider, each of said brake shoes having a brake lining mounted thereon;  
       a cam rotatably mounted to said brake spider and engaging each of said brake shoes, wherein rotation of said cam displaces said brake shoes and said brake linings;  
       an actuator shaft connected to said cam;  
       a slack adjuster connected to said actuator shaft whereby rotation of said slack adjustor cause direct rotation of said actuator shaft;  
       an attachment clevis pivotably connected to said slack adjustor, said slack adjustor having a mounting boss extending therefrom;  
       an actuator rod connected to said attachment clevis whereby displacement of said actuator rod causes displacement of said attachment clevis thereby rotating said slack adjustor which in turn rotates said actuator shaft and said cam to displace said brake shoes;  
       a switch mounted to said mounting boss and disposed between said slack adjustor and said attachment clevis such that when as said actuator rod is displaced a gap between said switch and said slack adjuster is changed, wherein when said actuator rod is displaced a predetermined distance, said slack adjustor engages said switch; and  
       a processing unit electrically connected to said switch, said processing unit generating a brake service signal when said slack adjuster engages said switch.